1. Field of the Invention
The present invention relates to an endoscopic imaging system in which a view image produced by an endoscope is projected.
2. Description of the Related Art
Endoscopes having elongated insertion units thereof inserted into body cavities or the like and thus assisting in observation of object regions, various kinds of examinations, and cures and treatments have been widely adopted in the past. Assume that an optical endoscope such as a rigid scope or fiberscope is employed. In this case, generally, a camera head included in an endoscopic imaging system is attached to an eyepiece unit of the endoscope, and an endoscopic image is projected and viewed on a monitor or recorded for future diagnosis. Moreover, various types of endoscopic imaging systems including an electronic endoscope that is provided with an imaging device such as a CCD have been put to use.
An endoscopic image projected by an endoscopic imaging system may be recorded for use in a clinical record or thesis. In this case, generally, the image has been filmed as a photograph in the past. Alternatively, the image has been recorded as a motion picture on videotape by means of a VTR, or recorded as digital image data on an information-recording device such as a hard disk. Recently, a PC card having a memory incorporated as a card-shaped compact portable recording medium therein has become popular.
A conventional endoscopic imaging system has not been designed so that a freely-detachable compact portable recording medium such as a PC card or any other expansion unit that has an external expansion capability can be detachably attached to a main processor unit such as a camera control unit. If a medium can be mounted directly in the main processor unit, it would be quite convenient for reading image data on the PC card or the like and help expand the capability of the system readily. However, as far as the conventional system is concerned, an expansion slot in which the expansion unit is mounted must be included separately. This may lead to a complex system configuration and time-consuming handling and invite an increase in cost.
Moreover, a conventional endoscopic image to be recorded as a digital signal is compressed at a certain level of compressibility and then written on a recording medium according to the JPEG or the like. This poses a problem of poor use efficiency of the recording medium. Otherwise, an endoscopic imaging system permitting manual change of levels of compressibility is available. However, since a level of compressibility must be changed to another at every endoscopic examination, there arises a problem that handling becomes a nuisance. Another problem is that this feature is unacceptable at a medical site at which it is hard to touch the system.
Moreover, image quality such as a resolution requested for a medical image varies depending on an employed endoscope or solid-state imaging device, a medical field, or a lesion concerned. Image quality dealt with ranges from high quality permitting a high resolution to low quality suffering from a low resolution. If a certain level of compressibility is always used for compression, image data may be recorded at an unnecessarily low level of compressibility. This poses a problem that the use efficiency of a recording medium deteriorates.
Moreover, the situation of an object to be represented by an endoscopic image varies depending on a field in which the endoscopic imaging system is employed. For example, when a large-diameter laparoscope is employed, a picture size corresponds to a full size of a monitor screen. The tone of an object image is reddish as a whole. In the field of urology, a small-diameter rigid scope is employed. The picture size corresponds to the size of part of the monitor screen. The tone of an object image is whitish.
For coping with the various use situations, a technology has been disclosed in, for example, Japanese Unexamined Patent Publication No. 7-194527. Herein, a ROM in which setting data is stored is incorporated in an endoscope. A control unit reads the setting data, and modifies a sequence of controlling light adjustment or the like. However, a rigid scope employed in a surgical procedure and a camera head included in an endoscopic imaging system may be used in combination. A plurality of types of endoscopes may be attached to the camera head. There is difficulty in storing the setting data in the endoscopes. Even when the camera head is provided with a ROM for storing the setting data, it is rather meaningless.
As mentioned above, a ROM in which setting data is stored is incorporated in an endoscope, and a control unit references the setting data to modify a setting for an operation such as light adjustment. Thus, the conventional system is adjusted to specifications for endoscopes that are different from field to field, situations of objects, and other different use situations. However, an endoscope system may be constructed by combining an optical endoscope such as a rigid scope and a camera head included in an endoscopic imaging system. In this case, there are problems in that it is hard to store setting data in the endoscope, and a setting for an operation such as light adjustment cannot be modified according to a use situation.
Moreover, when the conventional endoscopic imaging system is employed, a produced endoscopic image may be recorded on a compact portable recording medium which is freely attachable and detachable, such as a PC card. In this case, the recorded situation of image data on the medium is unclear to a user. This may result in such a drawback that necessary image data cannot be recorded or stored reliably. That is, an image cannot be recorded because of insufficient capacity, or previously recorded image data is overwritten. Moreover, if the PC card is improperly inserted or connected, recording of an image may fail.